Qtouch usable at wet condition?

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#1
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I just wonder: can Qtouch be used when it gets wet?

I understand that it is a capacitive technology. I have some bad experiences with cheap calipers in workshop environment. They work perfect, but as soon as some cooling agent or water droplets come near to the sensors the reading goes totally wrong.
Therefore I use only inductive calipers by now.

Will Q-touch be usable under these conditions, or what has to be done to make it useable?

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According to the presentation here in Melbourne last September ... yes. An application where water was flowing continuously across the touch switches was described as working in a messy pub.

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

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Quote:

According to the presentation here in Melbourne last September ... yes. An application where water was flowing continuously across the touch switches was described as working in a messy pub.

Clean water may not be too bad. But IME there are issues with certain fluids; here we call it the "409 test" (that is the name of a household cleaner). Unscientifically we speculate that it has very high conductivity and affects the fields.

So try with Windex or 409 or Fantastic or similar cleaners and see what you get. A wipe with a damp cloth should bring things back to normal.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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@valusoft
I am not yet totally convinced. I think that what you mention is that it is waterproof in the sense that it is fully enclosed (like the caliper example). Water will not reach the electronics.
But are the readings still accurate? Especially when the water is not regular distributed over the surface (you mention a continuous flow...).
At workshop conditions there are all kinds of irregular dirts like grease, waterdroplets, wet fingers, or gloves.

I would love to see some examples...!

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I would love to see some examples...!

The demo boards are quite inexpensive. I suggest getting one and trying it out.

Industrial-thickness rubber gloves are no problem. In general, wet/clean water seems fine as well.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Thank you for your answers.

I found some examples here http://www.atmel.com/products/bsw/applications.asp?family_id=697

I have also been reading some of the application notes. The water problem is recognised. I draw the conclusion that it may require some (or a lot?) skills and experiments to get a touch screen working properly under the conditions I mentioned.

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I have a metal surface, and a metal button. If I spill some water and it bridges across both it will trigger easily. However, this is a worst case scenario, as there is no plastic/glass insulation layer on top.

btw they do make IP67 rated calipers, but they are probably just as expensive as the inductive ones.

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Quote:
btw they do make IP67 rated calipers, but they are probably just as expensive as the inductive ones.

Seems they do

http://www.mitutoyo.com/ProductT...

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I am happy with this. It costs about €100
http://www.tesabs.ch/multimedia/docs/2008/05/elec_calipers.pdf

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in wet environments:
use not QTouch but QMatrix method
It will work fine as long as the water is not coupling between key and Gnd (e.g. metal bezel)
If the water can reach Gnd, no Cap tech will work...